I have changed my master password 2,5 days ago. After the change I did observe that all credentials are empty (only the URL are there, username and password fields and notes are empty). My vault isn't empty, there is only a lot of information missing. All my devices have the same issue, also at lastpass.com. This is a major issue since access to a 200+ sites are in this vault.
I can only guess what happened, perhaps corruption during the re-encrypting after I changed my password by Lastpass. LastPass support should look into this, but they didn't respond to my support ticket for last 48 hours as premium user. Hence am I trying my luck at this support forum.
Does anyone know if I can restore my vault to for example the one of last weekend myself?
this can be a sync issue, you can probably fix it by
1)Going to your LastPass Icon > More Options > Advanced > Refresh Sites for forcing a sync to your account.
2) clearing your local cache (LastPass Icon > More Options > Advanced > Clear Local Cache)
3)Log off and re-log or revert your account to its previous state. Check the data, and change it again.